[Simh] pdp7/decsys bug?

[J. David Bryan]

On Tuesday, May 15, 2007 at 13:49, Carl Lowenstein wrote:

> Four-decade-old memory of PDP-8 Fortran is telling me that there was at
> least one variety that used the hardware Floating-point Unit.

That's the thought I had, although I know nothing about the PDP-7.  If a FP 
instruction is being executed without a FP unit, it's possible that the 
value wouldn't be set properly.

The OP can test this by doing "DEPOSIT STOP_INST 1" from the "sim>" prompt 
before running the failing program.  This will cause SIMH to halt if an 
unimplemented instruction is executed (the default is to keep running with 
potentially erroneous results).

                                      -- Dave